With popularity of intelligent terminals, a quantity of intelligent terminals in a network is explosively increasing. To better meet a user requirement and improve information exchange efficiency, device-to-device (D2D) communication emerges as the times require. A D2D communications technology is a technology that implements direct communication between user equipments close to each other, without using a third party. The technology can improve spectrum utilization, relieve burden of a cellular network, increase a bit rate, and so on; and can support a new small-range point-to-point data service. Therefore, D2D communication plays an extremely important role in future evolution of communications networks.
In a co-site-coverage D2D communication process, after obtaining a data transmission resource from a base station, a device A may directly transmit data to a device B in coverage of the same base station. When the device A has no data transmission resource, the device A may need to request the base station to allocate a data transmission resource to the device A. If an available quantity of electricity of the device A is excessively low or the device A is a device sensitive to energy consumption, energy consumption of the device A is further accelerated in the existing manner in which the device A directly requests the data transmission resource from the base station.